Power inverter suitable for a vehicle

ABSTRACT

A power inverter comprises at least a box-shaped housing; and a power module, a smoothing capacitor, a base plate made of a flat plate, and a rotating electric machine control circuit board arranged in order in the housing. The base plate is arranged with the fringes fixed to the inner wall surfaces of the housing, and the smoothing capacitor and rotating electric machine control circuit board are fixed.

This application is a continuation of U.S. patent application Ser. No.13/098,665, filed May 2, 2011, which is a continuation of U.S. patentapplication Ser. No. 11/696,786, filed Apr. 5, 2007, which in turnclaims the benefit of priority under 35 U.S.C. §119 to Japanese PatentApplication No. 2006-104922, filed Apr. 6, 2006, the disclosure of whichis incorporated by reference herein in its entirety. This application isrelated to U.S. application Ser. No. 11/600,124, filed Nov. 16, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power inverter, for example, a powerinverter suitable for a vehicle.

2. Description of the Related Art

A power inverter comprises an inverter, a smoothing capacitor connectedin parallel with a DC power supply terminal of the inverter, and acontrol circuit which controls the inverter. The inverter has aplurality of power semiconductors, and the plurality of inverters areused as a power module in unit of a predetermined number. Therefore, theinverter comprises one or more power modules including a plurality ofpower semiconductors.

It is known that such a power inverter configured as a unit comprises ahousing which mounts the power module, a second block which mounts thesmoothing capacitor, and a third block which mounts a control boardintegrating the control circuit, which are all stacked in order, whereinthe second block is fixed to the housing and the third block is fixed tothe second block.

A power inverter having such a configuration is disclosed in details,for example, in JP-A-2003-199363.

SUMMARY OF THE INVENTION

For a pure electric vehicle driven by motor power without using acombustion engine and a hybrid electric vehicle using a combustionengine together with a motor, there is a demand for an increase in theratio of the cabin to the entire vehicle capacity for better ridingcomfort. In order to mount a control unit in a smallest possible space,downsizing of the control unit is demanded. There is also a demand for adownsized power inverter electrically connected with a rotating electricmachine for vehicle. However, trend of on-board rotating electricmachines is toward increasing power resulting in a larger heat releasevalue than in early stages of development. Moreover, trend for largerpower induces the use of high voltages, increasing the size ofequipment. For this reason, the size of power inverters is steadilyincreasing.

A main object of the present invention is to provide a power inverterwhich prevents an increase in size.

A main invention disclosed in the present application is provided withat least one of the following features. Then, the features will beexplained briefly.

(1) A feature of the present invention is a power inverter comprising atleast a metal housing; and a coolant channel body, a power module, acapacitor, and a base plate arranged in the housing; wherein

the plurality of power modules are arranged on the side of the coolantchannel body, and the capacitor is fixed to the base plate.

(2) Another features of the present invention is a power invertercomprising at least a metal housing; and a coolant channel body, a powermodule, a capacitor, and a base plate arranged in the housing; whereincooling fins of the power module project into the channel of the coolantchannel body.

(3) Still another feature of the present invention is a power invertercomprising at least a metal housing, a coolant channel body, a powermodule, a rotating electric machine control circuit, and a base platearranged in the housing, wherein

the plurality of power modules are arranged on the side of the coolantchannel body, and the rotating electric machine control circuit is fixedto the base plate.

(4) Still another feature of the present invention is a power invertercomprising at least a metal housing and a plurality of power modulesarranged in the housing, each of the power modules being provided with aDC input terminal and an AC output terminal, wherein

the plurality of power modules are arranged so that the DC inputterminal of each power module be positioned at the center of the housingand the AC output terminal of each power module is positioned on thesides of the housing.

(5) Still another feature of the present invention is a power invertercomprising at least a metal housing, a coolant channel body, a pluralityof power modules, and a plurality of capacitor modules arranged in thehousing, wherein

the capacitor is fixed so that its terminal be positioned at the centerof the housing;

the plurality of power modules are arranged on the side of the coolantchannel body, the DC input terminal of each power module is arranged atthe center of the housing, the AC output terminal of each power moduleis arranged on the sides of the housing, and the DC input terminal ofthe power module arranged at the center of the housing is electricallyconnected with the terminal of the capacitor module at the center of thehousing.

(6) Still another feature of the present invention is a power invertercomprising at least a metal housing, a coolant channel body, a pluralityof power modules, a plurality of capacitor modules, and a rotatingelectric machine control circuit board arranged in the housing, wherein

the plurality of power modules is fixed so that the DC input terminal ofeach power module be positioned at the center of the housing, and the ACoutput terminal of each power module is positioned on the sides of thehousing;

the plurality of capacitors are fixed so that the terminal of each ofthe plurality of capacitors be arranged at the center of the housing;and

the DC input terminal of the power module arranged at the center of thehousing is electrically connected with the terminal of the capacitormodule at the center of the housing.

(7) Still another feature of the present invention is a power invertercomprising at least a metal housing, a coolant channel body, a pluralityof power modules, a plurality of capacitor modules, a rotating electricmachine control circuit board, and a metal base plate arranged in thehousing, wherein

an opening is installed in the coolant channel body, a cooling fin isinstalled in each of the plurality of power modules, the cooling fins ofthe plurality of power modules project into the channel from the openingof the coolant channel body, and the opening is closed by the powermodule; and

the plurality of capacitor modules and the rotating electric machinecontrol circuit boards are prepared on the base plate.

(8) Other features of the present invention will be further explained inthe following embodiments.

An effect of the present invention is that a power inverter can bedownsized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram showing a hybrid electric vehicle which canmount the power inverter according to an embodiment of the presentinvention.

FIG. 2 is a disassembly perspective view showing the overallconfiguration of the power inverter according to the embodiment of thepresent invention.

FIG. 3 is a disassembly perspective view showing the overallconfiguration of the power inverter according to the embodiment of thepresent invention, viewed from a different direction from FIG. 2.

FIG. 4 is a disassembly perspective view showing the overallconfiguration of the power inverter according to the embodiment of thepresent invention, viewed from a different direction from FIG. 2 andFIG. 3.

FIG. 5 is an appearance perspective view showing the power inverteraccording to the embodiment of the present invention.

FIG. 6 is a left-half partial circuit diagram showing circuit boards tobe mounted on the power inverter and connections between these circuitboards, according to the embodiment of the present invention, whichforms a complete diagram when combined with FIG. 7.

FIG. 7 is a right-half partial circuit diagram showing circuit boards tobe mounted on the power inverter and connections between these circuitboards connections between these circuit boards and, which forms acomplete diagram when combined with FIG. 6.

FIG. 8 is a diagram showing the power inverter connections between thesecircuit boards, viewed from the front wall.

FIG. 9 is a cross-sectional view taken along the VIII-VIII line of FIG.5.

FIG. 10 is a cross-sectional view showing a signal connector to bemounted on the power inverter and a configuration thereof, according tothe embodiment of the present invention.

FIG. 11 is a plan view showing a condition where the power modules andthe gate drive circuit boards are arranged in the housing of the powerinverter of the present invention.

FIG. 12 is a plan view showing a condition where the capacitor modulesare arranged in the housing of the power inverter of the presentinvention.

FIGS. 13A and 13B are diagrams schematically showing capacitor modulesto be mounted on the power inverter according to the embodiment of thepresent invention, and also a cross-sectional view at a planeperpendicularly intersecting with the longitudinal direction of eachcapacitor module.

FIG. 14 is a side elevation view showing the power inverter according tothe embodiment of the present invention, viewed from the terminal boxattachment side.

FIG. 15 is a plan view showing a condition where the second block isarranged in the housing of the power inverter of the present invention,as well as the rotating electric machine control circuit board mountedon the second block B.

FIG. 16 is a diagram showing an arrangement aspect of the power inverterof the present invention in the vehicle engine room.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following explains embodiments of the power inverter by the presentinvention with reference to the accompanying drawings.

(Electric Vehicle 100)

FIG. 1 is a schematic diagram showing a hybrid electric vehicle whichcan mount the power inverter according to an embodiment of the presentinvention. A power inverter 200 according to the present invention canobviously be applied also to a pure electric vehicle, and many of basicconfigurations and operations are common to a hybrid electric vehicleand a pure electric vehicle. Therefore, the following explains someembodiments of hybrid electric vehicle as a representative case.

A hybrid electric vehicle 100 having front wheels 110 and rear wheels114 is provided with an engine 120, a first rotating electric machine130, a second rotating electric machine 140, and a battery 180 whichsupplies high-voltage DC power to the first rotating electric machine130 and second rotating electric machine 140. Actually, a battery forsupplying low-voltage power (14V power) is further mounted to supply thepower to later-mentioned control circuits. However, the battery is notshown. The rotational torque based on the engine 120, the first rotatingelectric machine 130, and the second rotating electric machine 140 istransmitted to a transmission control unit 154 and a differential gear160; and transmitted to the front wheels 110 through axles 112.

A transmission control unit 154 which controls the transmission 150, anengine control unit 124 which controls the engine 120, the rotatingelectric machine control circuit of the rotating electric machinecontrol circuit board 700 which controls the power inverter 200, and abattery control unit 184 which controls the battery 180 are connected toa vehicle control unit 170 through a local area network 174 which is asignal circuit 174.

The vehicle control unit 170 receives information indicating each statusfrom the transmission control unit 154, the engine control unit 124, thepower inverter 200, and the battery control unit 184, which are allsubordinate control units, through the signal circuit 174. Theinformation is used for integrated control of the vehicle from theviewpoint of the operability and safety of the vehicle. Integratedcontrol of the vehicle is attained through cooperative operation of eachof the control units. Control instructions for each control unit forrealizing integrated control of the vehicle are transmitted to eachcontrol unit from the vehicle control unit 170 through the signalcircuit 174. For example, the battery control unit 184 reports thedischarge status of the battery 180 and the condition of each cellbattery constituting the battery to the vehicle control unit 170. If thevehicle control unit 170 determines that the battery 180 needs to becharged based on the above-mentioned report, the unit issues aninstruction for power generation to the power inverter 200. The vehiclecontrol unit 170 manages the output torque of the engine 120, and thefirst rotating electric machine 130 and the second rotating electricmachine 140; obtains the total torque or torque distribution ratio ofthe output torque of the engine and the first rotating electric machine130 and second rotating electric machine 140 through operationalprocessing; and transmits control instructions based on processingresults to the transmission control unit 154, the engine control unit124, and the power inverter 200. The power inverter 200 controls thefirst rotating electric machine 130 and the second rotating electricmachine 140 based on the torque instructions, and controls theserotating electric machines so that the instructed torque power begenerated by either or both rotating electric machines.

The first rotating electric machine 130 and the second rotating electricmachine 140 are structured so as to operate as a motor or a dynamo. Forexample, when the first rotating electric machine 130 is operating as amotor, the second rotating electric machine 140 can be operated as amotor or a dynamo. As mentioned above, the vehicle control unit 170determines the distribution of the output torque of the engine and theoutput torque of the rotating electric machine as respective targettorque through operational processing based on the operating conditionof the vehicle; and transmits them to the power inverter 200 through thesignal circuit 174 using the target torque of the rotating electricmachine as a torque instruction. Based on the instructions, the powerinverter 200 determines through operational processing whether each ofthe first rotating electric machine 130 and the second rotating electricmachine 140 is to be operated as a motor or a dynamo, and controls thefirst rotating electric machine 130 and the second rotating electricmachine 140.

However, as another embodiment, it would be possible to determinewhether the first rotating electric machine 130 and the second rotatingelectric machine 140 are to be operated as a motor or a dynamo throughoperational processing by the vehicle control unit 170. With thismethod, the vehicle control unit 170 determines the torque to begenerated in the case of motor operation of the first rotating electricmachine 130 or the second rotating electric machine 140, or the power tobe generated in the case of dynamo operation; and transmits the contentsas an instruction to the power inverter 200 through the signal circuit174.

Irrespective of the methods, the power inverter 200 controls switchingoperation of power semiconductors constituting inverters in order tooperate the first rotating electric machine 130 and the second rotatingelectric machine 140 based on the instructions from the vehicle controlunit 170. The first rotating electric machine 130 and the secondrotating electric machine 140 are operated as a motor or a dynamothrough switching operation of these power semiconductors. In the caseof operation as a motor, the DC power from the high-voltage battery 180is applied to the inverter of the power inverter 200, the DC power isconverted to three-phase alternating current by controlling switchingoperation of the power semiconductors constituting inverters, thealternating current is supplied to the rotating electric machine 130 or140, and the rotating electric machine 130 or 140 generates rotationaltorque as a motor. In the case of operation as a dynamo, on the otherhand, the rotor of the rotating electric machine 130 or 140 is rotatedby rotational torque from external, and three-phase AC power isgenerated in stator winding of the above-mentioned rotating electricmachine based on this rotational torque. The generated three-phase ACpower is converted to DC power by the power inverter 200, the DC poweris supplied to the high-voltage battery 180, and the battery 180 ischarged by the DC power.

It would be possible to mechanically connect the engine 120 directlywith the first rotating electric machines 130 and the second rotatingelectric machine 140 shown in FIG. 1 through a rotating shaft. It wouldalso be possible that these rotating electric machines are connectedthrough gears or clutches. When the first rotating electric machine 130and the second rotating electric machine 140 are directly connected withthe engine 120, the first rotating electric machine 130 and the secondrotating electric machine 140 rotate in direct proportion to therotational speed of the engine. Therefore, the rotational speed of thefirst rotating electric machine 130 and the second rotating electricmachine 140 varies over a wide range from a stop condition to high-speedrotating condition, making it necessary for the rotating electricmachines to endure high-speed rotation and have a sufficient mechanicalstrength. Moreover, if the first rotating electric machine 130 and thesecond rotating electric machine 140 are constantly rotating, iron lossconstantly occurs which becomes large particularly in high-speedrotations. On the other hand, this system has advantages of a simplestructure and low cost.

Moreover, when the first rotating electric machine 130 and the secondrotating electric machine 140 are connected with the drive mechanism ofthe vehicle through clutches or gears, there is an advantage that thefluctuation range of the rotational speed of the first rotating electricmachine 130 and the second rotating electric machine 140 can be reduced.Moreover, the first rotating electric machine 130 and the secondrotating electric machine 140 can be disconnected from the drivemechanism of the vehicle as required, which may prevent the operationefficiency from being reduced by iron loss of the rotating electricmachines, etc. On the other hand, this system has a complicatedstructure resulting in high cost.

As shown in FIG. 1, the power inverter 200 comprises a capacitor module300 having a plurality of smoothing capacitors for reducing voltagefluctuation of the DC power supply, a power module 500 including aplurality of power semiconductors, a board (hereafter referred to asgate drive circuit board) 600 including a gate drive circuit whichcontrols switching operation of the power module 500; and a board(hereafter referred to as rotating electric machine control circuitboard) 700 including a rotating electric machine control circuit whichgenerates a signal for determining the time width of the above-mentionedswitching operation, i.e., a PWM signal for controlling pulse-widthmodulation.

When the power module 500 is electrically connected, the powersemiconductors included in the power module 500 are electricallyconnected to form an inverter circuit. A signal for controlling thepower semiconductors constituting the above-mentioned inverter circuitis generated by the rotating electric machine control circuit board 700and then sent to the gate drive circuit board 600. The gate drivecircuit board 600, so-called a gate drive circuit for the powersemiconductors, generate a gate drive signal to be supplied to the gateof each power semiconductor. The gate drive signal is sent to the gateof each power semiconductor. Each power semiconductor performs switchingoperation based on the gate drive signal.

For the capacitor module 300, the power module 500, the gate drivecircuit board 600, and the rotating electric machine control circuitboard 700, detailed circuits and operations will be explained later.

The high-voltage battery 180 is a rechargeable battery, such as a nickelhydride battery or a lithium ion battery, which outputs 300V, 600V, orother high-voltage DC power.

(Overall Configuration of Power Inverter)

FIG. 2, FIG. 3, and FIG. 4 are disassembly perspective views of thepower inverter 200, schematically showing a configuration of the powerinverter 200. FIG. 2, FIG. 3, and FIG. 4 are disassembly perspectiveviews of the power inverter 200, viewed from different directions.

The power inverter 200 has a box-shaped housing 210, and a coolantchannel body 220 including a coolant channel 216 for coolant circulationis installed at the bottom of the housing 210. A coolant inlet pipe 212for supplying coolant to the coolant channel 216 and a coolant outletpipe 214 are fixed to the bottom of the housing 210 in such a way thatthe pipes project to the outside of the housing 210.

The power module 500 explained with reference to FIG. 1 comprises afirst power module 502 and a second power module 504 arranged side byside in the housing 210. The first power module 502 and the second powermodule 504 are provided with cooling fins 506 and 507, respectively. Onthe other hand, the coolant channel body 220 is provided with openings218 and 219 which connect to the channel. By fixing the first powermodule 502 and second power module 504 above the cooling channel 216,the cooling fins 506 and 507 project into a channel 216 from openings218 and 219, respectively, prepared in the coolant channel body 220. Theopenings 218 and 219 are closed by a metal wall around cooling fins 506and 507, respectively, to prevent leak of coolant and form a coolantchannel. This first power module 502 and the second power module 504 arearranged on both sides of a virtual line perpendicularly intersectingwith the sidewall surface on which the coolant inlet pipe 212 and thecoolant outlet pipe 214 are formed. The coolant channel formed insidethe coolant channel body 220 extends from the coolant inlet pipe 212 ina longitudinal direction of the housing bottom to the other end. Then,the coolant channel is turned round in U-shape at the other end andextends again in a longitudinal direction of the housing bottom to theoutlet pipe 214. A pair of parallel channels in the above-mentionedlongitudinal direction are formed in the coolant channel body 220, andthe openings 218 and 219, through which respective channel penetrates,are formed in the coolant channel body 220. The first power module 502and the second power module 504 are fixed to the coolant channel body220 along the above-mentioned channel. Efficient cooling is accomplishedby the cooling fins prepared in the first power module 502 and thesecond power module 504, which project into the channel. At the sametime, an efficient cooling structure can be realized by the coolingsurfaces of the first power module 502 and the second power module 504,which are firmly attached to the coolant channel body 220 made of metal.Furthermore, since the openings 218 and 219 are closed by the coolingsurface of the first power module 502 and the second power module 504,respectively, the structure is downsized while improving the coolingperformance.

A first drive circuit board 602 and a second drive circuit board 604 arearranged side by side, and are stacked on the power module 502 andsecond power module 504, respectively. The first drive circuit board 602and second drive circuit board 604 constitute the gate drive circuitboard 600 explained with reference to FIG. 1.

The first drive circuit board 602 arranged above the power module 502 isformed in a slightly smaller size than the first power module 502 fromthe two-dimensional standpoint. In FIG. 2, FIG. 3, and FIG. 4, onlyterminals arranged side by side on both sides of the first power module502 are exposed and observed, and the most part of the power module 502is hidden by the first drive circuit board 602. Likewise, the seconddrive circuit board 604 arranged above the power module 504 is formed ina slightly smaller size than the second power module 504 from thetwo-dimensional standpoint. In FIG. 2, FIG. 3, and FIG. 4, onlyterminals arranged side by side on both sides of the second power module504 are exposed and observed, and the most part of the power module 504is hidden by the second drive circuit board 604.

The coolant inlet pipe 212 and the coolant outlet pipe 214 are formed ona side face of the housing 210, and an opening 260 is further formed onthis side. A signal connector 282 is arranged at the opening 260. Insidethe housing 210 at the attachment position of the connector 282 arrangedare a noise reduction board 560 and a second discharge board 520 whichare fixed in close vicinity to the connector 282. The noise reductionboard 560 and second discharge board 520 are fixed so that theirattachment surface be in parallel with the attachment surface of thefirst power module 502 and second power module 504.

The noise reduction board 560 is arranged below the second dischargeboard 520 in stacked manner and therefore hidden by the second dischargeboard 520, for example, in FIG. 2, FIG. 3, and FIG. 4. The noisereduction board 560 and second discharge board 520 are sufficientlyspaced from the power module 500 and the gate drive circuit board 600including a gate drive circuit in the height direction of the housing210. The gate drive circuit board 600 comprises a plurality of boards:the first drive circuit board 602 and the second drive circuit board604.

The capacitor module 300 having a plurality of smoothing capacitors isarranged above the plurality of drive circuit boards 602 and 604. Thecapacitor module 300 actually includes a first capacitor module 302 anda second capacitor module 304 arranged above the first drive circuitboard 602 and the second drive circuit board 604, respectively. Thefirst capacitor module 302 and the second capacitor module 304 are fixedto the base plate 320, and the electrodes are configured so as to beconnected with the power module 500.

The flat base plate 320 is fixed above the first capacitor module 302and the second capacitor module 304 in such a way that its fringes arefirmly attached to the inner wall surfaces of the housing 210. The baseplate 320 supports and fixes the first capacitor module 302 and secondcapacitor module 304 on the side of the above-mentioned first and secondpower modules, and the rotating electric machine control circuit board700 on the opposite side. And this base plate 320 made of a metalmaterial, like the housing 210 for example, is configured so that heatgenerated in the first capacitor module 302 and second capacitor module304, and the rotating electric machine control circuit board 700 goesinto the housing 210 for cooling.

As mentioned above, the power module 500, the gate drive circuit board600, the noise reduction board 560, the second discharge board 520, thecapacitor module 300, the base plate 320, and the rotating electricmachine control circuit board 700 are stored in the housing 210; and theopening at the top of the housing 210 is closed by a metal cover 290.

Moreover, when the sidewall of the housing 210 on which the coolantinlet pipe 212 and coolant outlet pipe 214 are installed is positionedas the front side, a terminal box 800 is attached, for example, on theright-hand sidewall of the housing. The terminal box 800 includes DCpower terminals 812 for supplying DC power from the battery 180 and DCpower terminal blocks 810 prepared therein, and AC power terminals 822for connecting the first rotating electric machine 130 and the secondrotating electric machine 140 and AC terminal blocks 820 preparedtherein.

The DC power terminal blocks 810 are electrically connected throughbusbars to the electrodes of the first capacitor module 302 and secondcapacitor module 304, and the AC terminal blocks 820 are electricallyconnected through busbars to the AC output terminals of the plurality ofpower modules 502 and 504 constituting the power module 500.

The configuration of the terminal box 800 is such that a bottom plate844 arranging the DC power terminal blocks 810 and a cover 846 areattached to a main part 840 to make it easier to assemble the terminalbox 800.

The thus-assembled power inverter 200 is configured in a very compactshape, as shown in the external view in FIG. 5.

Each of the DC power terminal blocks 810, DC power terminals 812, ACterminal blocks 820, and AC power terminals 822 functions as an ACoutput terminal, an AC terminal block, a DC input terminal, and a DCterminal block, respectively, based on a hybrid vehicle operation modein which, for example, the first rotating electric machine 130 isoperated as a dynamo, the three-phase AC power (regenerative energy)obtained is converted to DC power by the power inverter 200, and the DCpower is supplied to the battery 180.

(Electrical Circuit Diagram of Power Inverter)

Prior to detailed explanations of each of the above-mentioned componentsof the power inverter 200, circuit configurations and connection formsof the power module 500, the gate drive circuit board 600, the noisereduction board 560, the second discharge board 520, and the rotatingelectric machine control circuit board 700 will be explained togetherwith other parts, with reference to FIG. 6 and FIG. 7. FIG. 6 and FIG. 7are respectively left-half and right-half partial diagrams. CombiningFIG. 6 and FIG. 7 forms a complete circuit diagram.

Noise Reduction Board 560

First, each signal inputted to or outputted from the power inverter 200through the signal connector 282 passes the noise reduction board 560.These signals include signals from a resolver sensor 132 of the rotorbuilt in the first rotating electric machine 130, a signal from atemperature sensor 134 built in the first rotating electric machine 130,signals sent to and received from a vehicle control unit 170 and othercontrol units through the signal circuit 174, an activation signal 192sent from the vehicle control unit 170, a signal from a resolver sensor142 of the rotor built in the second rotating electric machine 140, asignal from a temperature sensor 144 built in the second rotatingelectric machine 140, and a failure detection signal 194 sent from thevehicle control unit 170. Signals sent through the signal circuit 174include a signal of engine rotational speed and a signal of acceleratoropening.

Furthermore, a low-voltage current sent from the low-voltage battery isalso configured to pass the noise reduction board 560. A positiveelectrode power from a 12V power supply 176 is outputted through anelectrode, a filter circuit 570, and then an electrode, from one side tothe other side of the noise reduction board 560. A negative electrodepower from the 12V power supply 176 is outputted through an electrode, adistribution layer, and an electrode.

Each of the above-mentioned signals other than the 12V power supply 176is outputted through an electrode, a bypass capacitor 562, and then anelectrode, from one side to the other side of the noise reduction board560. The bypass capacitor 562 is configured between a distribution layerin which each signal is transmitted and a distribution layer in whichthe negative electrode power from the 12V power supply is supplied.

The noise reduction board 560 having such a configuration reduces noisesuperimposed on each of the above-mentioned signals by means of thebypass capacitor 162 and supplies the signals to the rotating electricmachine control circuit board 700 mentioned later.

The noise reduction board 560 is formed on a board different from therotating electric machine control circuit board 700, physically spacedfrom the rotating electric machine control circuit board 700. Thisallows the noise reduction board 560 to be arranged at a desiredposition without being restrained by the attachment position of therotating electric machine control circuit board 700.

Physically separating a circuit (equivalent to a circuit on the noisereduction board 560 in the present embodiment) which remove noise in aninput signal from the rotating electric machine control circuit board700 having a comparatively large area is effective for downsizing therotating electric machine control circuit board 700. Furthermore, thenoise reduction board 560 can be arranged in a desired manner, forexample, it can be positioned in a plane in parallel with orperpendicular to the rotating electric machine control circuit board700, which is therefore very convenient for downsizing the powerinverter 200.

(Rotating Electric Machinery Control Circuit Board 700)

Each signal from the resolver sensor 132 and the temperature sensor 134of the above-mentioned rotor inputted through the noise reduction board560 is to be fed to a first microcomputer 702 through an interfacecircuit 732 on the rotating electric machine control circuit board 700.

Likewise, each signal from the resolver sensor 142 and the temperaturesensor 144 of the rotor inputted through the noise reduction board 560is to be fed to a second microcomputer 704 through an interface circuit742 on the rotating electric machine control circuit board 700.

Information from the communication circuit 174 is sent to the firstmicrocomputer 702 and second microcomputer 704 through the communicationdriver circuit 720. Moreover, information on the operating condition issent from the first microcomputer 702 and second microcomputer 704 tothe signal circuit 174 through the communication driver circuit 720 andthe noise reduction board 560 to predetermined equipment, for example,the vehicle control unit 170. The vehicle control unit 170 determineseach of operation modes of the vehicle, including the start, low-speedrunning, normal running (medium- and high-speed running), acceleration,deceleration, and braking modes. When the vehicle control unit 170determines the operation mode, it transmits a judgment result to thefirst microcomputer 702 and the second microcomputer 704, and then thefirst microcomputer 702 and the second microcomputer 704 control thefirst rotating electric machine 130 and the second rotating electricmachine 140, respectively, based on the result.

Control corresponding to the operation mode is such that, for example,mainly the first rotating electric machine 130 is operated as a motor inthe start or low-speed running mode of the vehicle. In the normalrunning mode of the vehicle, the engine 120 and the first rotatingelectric machine 130 are used together to run the vehicle with torque ofboth. In the rapid acceleration or high-load operation mode of thevehicle, the operation in the above-mentioned normal running mode isperformed, and the output power from the battery 180 is converted tothree-phase AC power which is then supplied to the second rotatingelectric machine 140. The two rotating electric machines are operated asa motor, the output torque is used to drive the vehicle, and the outputof the engine is further added to run the vehicle. In the decelerationor braking mode of the vehicle, the first rotating electric machine 130and the second rotating electric machine 140 are operated as a dynamo,the obtained three-phase AC power is converted to DC power by alater-mentioned inverter, and the DC power is supplied to the battery180 to charge it.

Upon reception of operation mode information from the vehicle controlunit 170, each of the first microcomputer 702 and the secondmicrocomputer 704 calculates operation timing of the powersemiconductors constituting inverters through operational processing. Atiming signal based on operation result of the first microcomputer 702is sent to the first drive circuit board 602 through an interfacecircuit 734. Moreover, a timing signal calculated and generated by thesecond microcomputer 704 is sent to the second drive circuit board 604through an interface circuit 744.

The output of a first current sensor 536 which detects a current valueflowing in each phase of the stator winding of the first rotatingelectric machine 130, and the output of a first temperature sensor 532built in the first power module 502 are captured in the firstmicrocomputer 702 through an interface circuit 736. The firstmicrocomputer 702 uses the captured output of the first current sensor536 to perform operational processing of the operation timing of theabove-mentioned power semiconductors for feedback control so thatcontrol based on a command value of the vehicle control unit 170 beperformed. The output of the temperature sensor 532 is used to diagnoseoperation failures.

Likewise, the output of a second current sensor 538 which detects acurrent value flowing each phase of the stator winding of the secondrotating electric machine 140, and the output of a second temperaturesensor 534 built in the second power module 504 are captured in thesecond microcomputer 704 through an interface circuit 746. The secondmicrocomputer 704 uses the captured output of the second current sensor536 to perform operational processing of the operation timing of theabove-mentioned power semiconductors for feedback control so thatcontrol based on a command value of the vehicle control unit 170 beperformed. The output of the second temperature sensor 534 is used todiagnose operation failures.

The first current sensor 536 and the second current sensor 538 areinstalled on the AC output terminal blocks 820 mentioned later.

The rotating electric machine control circuit board 700 is provided witha supervisory circuit 760. A failure detection signal from the vehiclecontrol unit 170, a superordinate control unit, obtained through thenoise reduction board 560 and the second discharge board 520 is inputtedto the supervisory circuit 760. The above-mentioned failure detectionsignal is generated if the vehicle control unit 170, a superordinatecontrol unit, determines that there is a danger in a high-voltageportion. If the supervisory circuit 760 receives this signal, it sendsan abnormal condition signal to the first microcomputer 702 as a resultof monitoring. Based on this signal, the operation of the first rotatingelectric machine 130 is stopped by the first microcomputer 702. In thiscondition, the vehicle is operated with the output torque of the engine120.

DC power is supplied from the 12V power supply 176 to a power supplycircuit 750 through the noise reduction board 560, and a stabilizedconstant voltage is outputted from the power supply circuit 750. Theoutput of the power supply circuit 750 is supplied to the firstmicrocomputer 702, the second microcomputer 704, and the interfacecircuit 732 on the rotating electric machine control circuit board 700,and to other circuits on the rotating electric machine control circuitboard 700.

(Gate Drive Circuit Board 600)

The gate drive circuit board 600 comprises the first drive circuit board602 and the second drive circuit board 604. Switching timing signalsgenerated by the first microcomputer 702 are inputted to the first drivecircuit board 602 through the interface circuit 734 of the rotatingelectric machine control circuit board 700. These timing signals areinputted to a U-phase driver circuit 632, a V-phase driver circuit 634,and a W-phase driver circuit 636 through an insulation circuit 622comprising, for example, a photo coupler. The output from each of thesedriver circuits 632, 634, and 636 is used as a drive signal forcontrolling switching operation of each power semiconductor in the firstpower module 502 mentioned later.

Moreover, the first drive circuit board 602 is provided with a voltagesensor circuit 638 which detects voltage in the driver circuits 632,634, and 636. As mentioned above, the output of the voltage sensorcircuit 638 is sent to the first microcomputer 702 through theinsulation circuit 622 and the interface circuit 736 of the rotatingelectric machine control circuit board 700.

The driver circuits 632, 634, and 636 are driven by constant voltagefrom a power supply circuit 612 installed on the first drive circuitboard 602. The 12V DC power from the signal connector 282 is supplied tothe power supply circuit 612 through the noise reduction board 560 andthe rotating electric machine control circuit board 700.

Switching timing signals generated by the second microcomputer 704 areinputted to the second drive circuit board 604 through the interfacecircuit 744 of the rotating electric machine control circuit board 700.These timing signals are inputted to a U-phase driver circuit 642, aV-phase driver circuit 644, and a W-phase driver circuit 646 through aninsulation circuit 624. The output from each of these drivers 642, 644,and 646 is used as a signal for controlling switching operation of eachpower semiconductor in a second power module 504 mentioned later.

Like the first drive circuit board 602, the second drive circuit board604 is provided with a voltage sensor circuit 648 which detects voltageof the driver circuits 642, 644, and 646. As mentioned above, the outputis sent to the second microcomputer 704 through the insulation circuit624 and the interface circuit 746 of the rotating electric machinecontrol circuit board 700.

The circuit including the driver circuits 642, 644, and 646 is driven bystabilized power from a power supply circuit 614 mounted on the seconddrive circuit board 604. The 12V power PW from the signal connector 282is supplied to the power supply circuit 614 through the noise reductionboard 560 and the rotating electric machine control circuit board 700.

(Insulation Circuits 622 and 624)

In the present embodiment, two different DC power supplies are prepared:a low-voltage battery and a high-voltage battery 180. These powersupplies are different not only in voltage but also in potential on themutual ground side. Normal operation can be attained even with differentground potentials by preparing insulation circuits 622 and 624. Forexample, even if the potential of the driver circuits 632, 634 and 636,the voltage sensor circuit 638, the driver circuits 642, 644 and 646,and the voltage sensor circuit 648 is different from the groundpotential of the rotating electric machine control circuit board, normaloperation are attained by the insulation circuits 622 and 624 withoutbeing affected by the potential difference. This also applies to acapacitor discharge control circuit later mentioned in details.

(Power Module 500)

The power module 500 shown in FIG. 1 includes the first power module 502and the second power module 504. Although not shown, the first powermodule 502 includes an inverter which includes a total of six powersemiconductors, each two being connected in series constituting each ofU-phase, V-phase, and W-phase bridge circuits. Both ends of each of theabove-mentioned bridge circuits are configured so that the DC voltagefrom the battery 180 be supplied thereto. If the current supplied to thefirst rotating electric machine 130 is large current, the configurationis such that a plurality of power semiconductors constituting theabove-mentioned inverter are arranged in parallel. The above-mentionedconfiguration also applies to the second power module 504.

Each power semiconductor of the U phase performs switching operationbased on a signal from the driver circuit 632 of the gate drive circuitboard 602; each power semiconductor of the V phase performs switchingoperation based on a signal from the driver circuit 634 of the gatedrive circuit board 602; and each power semiconductor of the W phaseperforms switching operation based on a signal from the driver circuit636 of the gate drive circuit board 602. Three-phase AC power isoutputted and supplied to the first rotating electric machine 130. Thecurrent of each layer is detected by the current sensor 536.

A temperature sensor 532 is installed in the first power module 502, anda signal therefrom is captured by the first microcomputer 702 throughthe interface circuit 736. If temperature rises, the current to thefirst rotating electric machine is suppressed to prevent damage to thepower module 502.

Likewise, the second power module 504 also includes an invertercomprising power semiconductors.

Each phase power semiconductor constituting the inverter performsswitching operation based on signals from driver circuits 642, 644, and646 of the gate drive circuit board 614 to output three-phasealternating current or convert the output of the second rotatingelectric machine 140 to direct current. The current of each phase isdetected by the current sensor 538. Moreover, the power module 504includes a temperature sensor 534 and the output of the temperaturesensor 534 is inputted to the second microcomputer 704 through theinterface circuit 746. The control current of the inverter is suppressedaccording to temperature rise to prevent damage to the power module 504.Capacitor module 300, and First and Second Discharge Resistors

The capacitor module 300 in FIG. 1 includes the first capacitor module302 and the second capacitor module 304 which are connected in parallel.The first capacitor module 302 and the second capacitor module 304 areconnected in parallel between both lines of a busbar 860, which act asDC power lines, and high-voltage DC power is supplied from the DC highvoltage battery 180 to the busbar 860. The busbar 860 is connected toboth DC input terminals of the inverter circuit of each of the powermodule 502 and the second power module 504.

Moreover, a first discharge resistor (not shown) and a second dischargeresistor 524 are connected in parallel with the first capacitor module302 and second capacitor module 304. Each of these resistors is used todischarge electric charges accumulated in the first capacitor module 302and the second capacitor module 304. The second discharge resistor 524of these resistors is used to rapidly discharge electric chargesaccumulated in the first capacitor module 302 and the second capacitormodule 304, which is performed through control by the second dischargeboard 520.

(Second Discharge Board 520)

A capacitor discharge control circuit 522 is provided on the seconddischarge board 520. This is because electric charges accumulated in thefirst capacitor module 302 and second capacitor module 304 are rapidlydischarged by inputting a failure detection signal 194 from the signalconnector 282 through the noise reduction board 560.

The capacitor discharge control circuit 522 is provided with atransistor, a switching element 526, which operates when the failuredetection signal 194 is inputted. This transistor 526 is connected inseries with the second discharge resistor 524. With the transistor 526,the second discharge resistor 524 forms a closed circuit with respect tothe first capacitor module 302 and second capacitor module 304. With theconduction of the transistor 526, electric charges accumulated in thefirst capacitor module 302 and the second capacitor module 304 aredischarged through the second discharge resistor 524.

High voltage, for example 300V or 600V, from the battery 180 is appliedto the capacitor discharge control circuit 522. This high-voltage powerdiffers from the ground potential of the noise reduction board 560 orthe rotating electric machine control circuit board. For normaloperation, the failure detection signal 194 is inputted to the capacitordischarge control circuit CDC through an insulation circuit 528comprising, for example, a photo coupler. The second discharge board 520is formed on a board different from the rotating electric machinecontrol circuit board 700, physically spaced from the rotating electricmachine control circuit board 700.

Moreover, voltage of about 12V is applied to the rotating electricmachine control circuit board 700 while high voltage, such as 300V to600V, is applied to the second discharge board 520. With physicalisolation between the two boards, therefore, the second discharge board520 can be sufficiently spaced from the rotating electric machinecontrol circuit board 700 so that the board 520 does not affect theboard 700.

Physically isolating a circuit (equivalent to a circuit on the seconddischarge board 520 in the present embodiment) which forcibly dischargeselectric charges accumulated in the first capacitor module 302 and thesecond capacitor module 304 from the rotating electric machine controlcircuit board 700 having a comparatively large area is effective fordownsizing the rotating electric machine control circuit board 700.Furthermore, the second discharge board 520 can be arranged in a desiredmanner, for example, so that it can be positioned in a plane in parallelwith or perpendicular to the rotating electric machine control circuitboard 700, which is therefore very convenient for downsizing the powerinverter 200.

(Each Configuration Component of Power Inverter 200)

The following explains in detail the configuration of each componentshown in FIG. 2 to FIG. 4.

Housing 210

The housing 210, made of a metal material for example aluminum,comprises an approximately rectangular box having a coolant channel bodyincluding a coolant channel at the bottom and an opening at the top.Taking into consideration the convenience of the following explanations,one of the above-mentioned four sidewalls of the housing 210 is referredto as front wall 232, and an adjacent sidewall to the right of the frontwall 232 is referred to as main sidewall 234.

FIG. 8 is a diagram showing the power inverter 200, viewed from thefront wall 232 of the housing 210.

At the bottom of the housing 210, two coolant channels are arranged,side by side, to circle around the bottom, providing a coolant channelbody 220 comprising a dual structure which sandwiches a space (notshown) to which the coolant is supplied. The front wall 232 of thehousing 210 is provided with a coolant inlet pipe 212 and a coolantoutlet pipe 214 connected to the above-mentioned space. The coolant canbe circulated at the bottom of the housing 210 by supplying the coolantto the above-mentioned space through the coolant inlet pipe 212 and thecoolant outlet pipe 214. Specifically, the housing 210 is provided witha coolant channel 216 at the bottom, through which the coolantcirculates.

Moreover, on the upside board (the board on the side facing to the powermodule 500) of the coolant channel body 220 forming the above-mentionedspace of this housing 210, each of openings 218 and 219 ranging from thefront wall 232 toward the opposite sidewall is formed almost at thecenter of each of two areas formed by a virtual center lineapproximately in parallel with the main sidewall 234, as shown in FIG.4.

A pair of power modules comprising the first power module 502 and thesecond power module 504 are arranged at the bottom of the housing 210.Each of the first power module 502 and the second power module 504 ispositioned above the coolant channel body 220. The cooling surfaces ofthe first power module 502 and the second power module 504 arerespectively provided with cooling fins 506 and 507 comprising a numberof pin-shaped projections arranged side by side. These cooling fins 506and 507 project into the openings 218 and 219 of the coolant channelbody 220. Furthermore, the above-mentioned openings are respectivelyclosed by the cooling surface of the power module 504 around the coolingfins 506 and 507, preventing leak and forming a sealed channel 216.

Cooling fins RDF1 and RDF2 of the first power module 502 and the secondpower module 504 and the openings 218 and 219 formed at the bottom ofthe housing 210 are shown in the FIG. 9 showing a section by theVIII-VIII line in FIG. 5.

With such a configuration, cooling by the coolant at the bottom of thehousing 210 is efficiently performed by cooling fins 506 and 507 of thefirst power module 502 and the second power module 504, respectively.Moreover, the configuration with which cooling fins 506 and 507 of thefirst power module 502 and the second power module 504 are insertedalong with the openings 218 and 219, respectively, is effective forpositioning the first power module 502 and the second power module 504with respect to the housing 210.

Moreover, on the front wall 232 of the housing 210, from which thecoolant inlet pipe 212 and coolant outlet pipe 214 project, anapproximately square opening 260 having a comparatively small area isformed at a position above the coolant inlet pipe 212 and the coolantoutlet pipe 214. The signal connector 282 later mentioned in detail willbe arranged so that it projects through the opening 260 from the insideof the housing.

Furthermore, on the main sidewall 234 of the housing 210, as shown inFIG. 3, an opening 262 having a comparatively small area and an opening264 having a comparatively large area ranging from the side of the frontwall 232 toward the side of the opposite sidewall (facing to the frontwall) are formed side by side on the opening side (upper position wherea cover CV is to be attached) of the housing 210. A terminal box 800later mentioned in detail will be arranged on the main sidewall 234 ofthe housing 210. The DC power terminal blocks 810 in the terminal box800 are electrically connect with the first capacitor module 302 and thesecond capacitor module 304 in the housing 210 through the opening262CH2, and the AC terminal blocks 820 in the terminal box 800 areelectrically connected with the first power module 502 and the secondpower module 504 in the housing 210 through the opening 264.

On the inner surface of each sidewall of the housing 210, as shown inFIG. 4, a plurality of convex parts PR are arranged side by side alongthe circumference. Each convex part PR ranges from the bottom of thehousing 210 toward the side of the opening end, i.e., in the heightdirection. The end faces of the convex parts are aligned immediatelybefore the above-mentioned opening end. The end face of each convex partPR is almost in parallel with the coolant channel body 220 at the bottomof the housing 210 and has a screw hole formed thereon. As latermentioned in detail, these convex parts PR support at their end facesthe base plate 320 on its fringes, which is arranged so as to close theopening of the housing 210 over a wide range. The base plate 320 is alsofixed by screws SC4 (refer to FIG. 15) screwed into the above-mentionedscrew holes through the base plate 320.

(Signal Connector 282)

FIG. 10 is a cross-sectional view showing the signal connector 282 andthe configuration in the vicinity. The signal connector 282 is arrangedat the opening 260 formed on the housing 210, projecting from the insideto the outside of the housing through the opening 260.

The signal connector 282 is fixed to the housing 210 through supportparts SM having an L-shaped section. Specifically, the signal connector282 is fixed to a flat part SM (1), out of support parts SM, in parallelwith the front wall 232 of the housing 210, and the flat part SM (1) isfixed to the inner surface of the housing 210 for example by a screwSC8, so that the signal connector be arranged in the opening 260.

The other flat part SM (2), out of the support parts SM, perpendicularlyintersects with the inner surface of the housing 210, i.e., is extendedapproximately in parallel with the bottom of the housing 210. The noisereduction board 560 is mounted on the underside of the flat part and thesecond discharge board 520 on the upper side thereof.

Here, the second discharge board 520 is mounted on the upper surface ofthe flat part SM (2) of support parts SM and arranged on the near sideof the opening (the side on which the cover 290 is to be attached) ofthe housing 210. The second discharge board 520 is arranged as mentionedabove because it is more prone to discharge breakdown than the noisereduction board 560, and this arrangement makes it easier to replace adischarge board CBD with a new one if discharge breakdown occurs.

Although not shown, the most part of wiring from the signal connector282 is connected to the noise reduction board 560. In this case, theconnector 282 and the noise reduction board 560 can be arranged in closevicinity to each other without obstacles, making it easy to arrangewiring.

Moreover, FIG. 10 shows the relationship in arrangement of the noisereduction board 560 and second discharge board 520 with respect to thepower module 500 and gate drive circuit board 600 mentioned later. Thenoise reduction board 560 and the second discharge board 520 arearranged maintaining a sufficient distance D from the power module 500and the gate drive circuit board 600, making it possible to reduceinfluences of noise from the power module 500 and the gate drive circuitboard 600.

Furthermore, from the two-dimensional standpoint, the noise reductionboard 560 and second discharge board 520 stacked thereon are configuredso that they are stacked on a part of the power module 500 and gatedrive circuit board 600. This means that the area of the housing 210,from the two-dimensional standpoint, can be made almost equal to thearea occupied by the power module 500 and gate drive circuit board 600;and that it is not necessary to take into consideration the occupiedarea of the noise reduction board 560 and the second discharge board520, allowing the housing 210 to be downsized.

(Power Module 500 and Gate Drive Circuit Board 600)

FIG. 11 is a plan view showing a condition where the power module 500and the gate drive circuit board 600 are arranged inside the housing210.

The first power module 502 and the second power module 504 constitutingthe power module 500 are arranged inside the housing 210, and arepositioned at a lower level than any other electrical componentsmentioned later. The first power module 502 and second power module 504drive the first rotating electric machine 130 (motor or dynamo) and thesecond rotating electric machine 140 (dynamo or motor), respectively.

The first power module 502 and the second power module 504 are arrangedside by side so that the short sides thereof are in parallel with thefront wall 232 of the housing 210 and the long sides thereof are inparallel with the main sidewall 234.

Moreover, each of the first power module 502 and the second power module504 has DC input terminals IT1 and IT2 and AC output terminals OT1 andOT2 arranged in the same direction, giving the same geometricalconfiguration. For example, by rotating the second power module 504 by180 degrees with respect to the first power module 502, DC inputterminals IT1 and IT2 are arranged so as to face to each other. In thiscase, the first power module 502 and the second power module 504 areslightly shifted in the longitudinal direction to arrange the DC inputterminals IT1 and IT2 so that mating terminals be arranged in thevicinity. As shown in FIG. 11, the DC input terminals IT1 and IT2 of thefirst power module 502 and the second power module 504 are arranged atthe center of the housing 210, and the AC output terminals OT1 and OT2are arranged along the sides of the housing 210.

Each of the first power module 502 and the second power module 504,although not shown, comprises an electric conductive board made of aheat conduction part for example copper; a weir-shaped case firmlyattached to the fringes on the upper surface of the electric conductiveboard; an insulating board soldered to the area surrounded by theabove-mentioned case of the above-mentioned electric conductive board;transistors (for example, insulated gate type bipolar transistors) anddiodes mounted on this insulating board, and distribution layers forconnecting these transistors and diodes; and a plurality of DC inputterminals IT and AC output terminals OT connected with thesedistribution layers and formed on the above-mentioned case. It would bepossible to use an IGBT instead of the above-mentioned transistor.

In FIG. 11, since the gate drive circuit boards 602 and 604 are stackedon the first power module 502 and the second power module 504,respectively, a central area where the above-mentioned transistors anddiodes or IGBT are mounted is hidden; instead, the DC input terminals ITand AC output terminals OT formed on the above-mentioned case areviewed.

As mentioned above, the DC input terminals IT1 and IT2 of the firstpower module 502 and the second power module 504 are formed side by sidealong the sides facing in close vicinity to each other, and the ACoutput terminals OT1 and OT2 of the first power module 502 and thesecond power module 504 are formed side by side along the other sides inparallel with the sides on which the DC input terminals IT1 and IT2 areformed. In other words, the DC input terminals IT of the power module500 are positioned on the inner sides of the first power module 502 andthe second power module 504 arranged side by side, and the AC outputterminals OT of the power module 500 are positioned on the outer sidesof the first power module 502 and the second power module 504 arrangedside by side.

The DC input terminals IT1 and IT2 of the first power module 502 and thesecond power module 504 are electrically connected with the terminals ofthe capacitor module 300 later mentioned in detail, and the AC outputterminals OT1 and OT2 of the first power module 502 and the second powermodule 504 are connected to the AC terminal blocks 820 in the terminalbox 800 later mentioned in detail.

Specifically, the AC output terminals OT1 of the first power module 502include terminals OT1 u, OT1 v, and OT1 w for the U, V, and W phases,respectively. Lead wires from the terminals OT1 u, OT1 v, and OT1 w arelead along one short side of each of the power modules 502 and 504arranged side by side; pass respectively through busbars BP1 u, BP1 v,and BP1 w attached on the main sidewall 234 of the housing 210; and arerespectively lead to lead terminals OL1 u, OL1 v, and OL1 w projectingthrough the opening 264 formed on the main sidewall 234 of the housing210.

Likewise, the AC output terminals OT2 of the second power module 504include terminals OT2 u, OT2 v, and OT2 w for the U, V, and W phases,respectively. Lead wires from the terminals OT2 u, OT2 v, and OT2 w passrespectively busbars BP2 u, BP2 v, and BP2 w attached on the mainsidewall 234 of the housing 210; and are respectively lead to leadterminals OL2 u, OL2 v, and OL2 w projecting through the opening 264.

Cooling fins 506 and 507 projecting into the channel are prepared on thecooling surfaces of the first power module 502 and the second powermodule 504, respectively. Screw holes are formed around the cooling finsof the first power module 502 and the second power module 504. Eachpower module is fixed to the bottom of the housing 210 through thesescrew holes. A gate drive circuit board 700 is arranged above a powermodule PUM. The gate drive circuit board 700 also comprises a pair ofthe first drive circuit board 602 and the second drive circuit board 604which are different units. The first drive circuit board 602 is arrangedabove the power module 502 and fixed to the power module 502 with screwsSC2, and the second drive circuit board 604 is arranged above the secondpower module 504 and fixed to the power module 504 with screws SC2.

The first drive circuit board 602 and the second drive circuit board 604are configured as circuit boards for supplying switching signal to thefirst power module 502 and the second power module 504, respectively, asmentioned above.

A harness HN is lead to the first drive circuit board 602 and the seconddrive circuit board 604 through a connector CN prepared on the mainsurface. The harness HN is connected to the rotating electric machinecontrol circuit board 700 mentioned later.

In the description of the present embodiment, although the power module500 and the gate drive circuit board 700 are used as different units, itwould be possible to integrate the gate drive circuit into the powermodule 500 board. The present embodiment is more desirable in terms ofthe cooling efficiency and downsizing of the equipment.

(Capacitor Module 300)

FIG. 12 is a plan view showing a condition where the capacitor module300 including a smoothing capacitor is arranged in the housing 210.

The capacitor module 300 is arranged in the housing 210, and ispositioned above the gate drive circuit board 600.

Moreover, the capacitor module 300 comprises the first capacitor module302 and the second capacitor module 304. Each of the first capacitormodule 302 and the second capacitor module 304 includes five to six filmcapacitors (capacitor cells), for example, stored in a rectangularparallelepiped case made of resin material.

The first capacitor module 302 and the second capacitor module 304 arearranged side by side. The first capacitor module 302 is arranged abovethe first drive circuit board 602, and the second capacitor module 304is arranged above the second drive circuit board 604.

FIGS. 13A and 13B are diagrams schematically showing the first capacitormodule 302 and the second capacitor module 304, and also across-sectional view at a plane perpendicularly intersecting with thelongitudinal direction of the first capacitor module 302 and the secondcapacitor module 304. FIG. 13A and FIG. 13B are cross-sectional viewsshowing cross sections of the first capacitor module 302 and the secondcapacitor module 304, respectively, at two different positions in thelongitudinal direction.

The first capacitor module 302 and the second capacitor module 304 areslightly spaced and, for example, mutually fixed by the electrodes ET1and ET2 arranged at the bottom so as to bridge the above-mentionedspaced section. These electrodes ET1 and ET2 are connected to the DCinput terminals IN of the first power module 502 and second power module504, respectively.

The electrode ET1, in appearance, includes a wide conductor lead fromthe inside outward at the bottom of the case CS1 of the first capacitormodule 302 and bent toward the first power module 502 and a junction JN1connecting the conductor to the DC input terminal IN of the first powermodule 502. The electrode ET1 is configured as a three-layer structurecomprising a first electric conductive board FC1, an insulated sheetIS1, and a second electric conductive board SC1 in order. One electrodeof a film capacitor FIC1 in the first capacitor module 302 is connectedto one of the electric conductive boards FC1 and SC1, and the otherelectrode of the film capacitor FIC1 is connected to the other of theelectric conductive boards FC1 and SC1. At the junction JN1 where theelectrode ET1 is connected with the DC input terminal IN of the firstpower module 502, one of the electric conductive boards FC1 and SC1 isto be connected according to each of a plurality of DC input terminalsIN arranged side by side. (In FIG. 13A, the electric conductive boardFC1 is connected; in FIG. 13B, the electric conductive board SC1 isconnected).

Likewise, the electrode ET2, in appearance, includes a wide conductorlead from the inside outward at the bottom of the case CS2 of the secondcapacitor module 304 and bent toward the second power module 504 and ajunction JN2 connecting the conductor to the DC input terminal IN of thesecond power module 504. Likewise, the electrode ET2 is configured as athree-layer structure comprising a first electric conductive board FC2,an insulated sheet IS2, and a second electric conductive board SC2 inorder. One electrode of a film capacitor FIC2 in the second capacitormodule 304 is connected to one of the electric conductive boards FC2 andSC2, and the other electrode of the film capacitor FIC2 is connected tothe other of the electric conductive boards FC2 and SC2. At the junctionJN2 where the electrode ET2 is connected with the DC input terminal INof the second power module 504, one of the electric conductive boardsFC2 and SC2 is to be connected according to each of a plurality of DCinput terminals IN arranged side by side.

The electrode ET1 and ET2 of the first capacitor module 302 and thesecond capacitor module 304 are electrically connected with the firstpower module 502 and the second power module 504, respectively, when thefirst electric conductive board FC and the second electric conductiveboard SC are respectively connected to a pair of DC input terminals inthe so-called U-phase arm, a pair of DC input terminals in the V-phasearm, and a pair of DC input terminals in the W-phase arm in the powermodule 500. This is why six electrodes ET1 and ET2 (shown as symbols JNin FIG. 12) are viewed between the first capacitor module 302 and thesecond capacitor module 304 in FIG. 12, which correspond to a pair of DCinput terminals IN on each of the three arms.

As mentioned above, the electrodes ET1 and ET2 are configured as athree-layer structure comprising the first electric conductive board FC,the insulated sheet IS, and the second electric conductive board SC inorder so that the direction of current flowing in the first electricconductive board FC be opposite of that of current flowing in the secondelectric conductive board SC. This aims at inducing the coupling ofinductance to reduce the inductance.

As shown in FIGS. 13A and 13B, the electrodes ET1 and ET2 can beconfigured so that they are physically connected to each other inadvance at the respective junctions JN1 and JN2 at which they areconnected with the DC input terminals IN of the second power module 504.Alternatively, unlike FIGS. 13A and 13B, the electrodes can also beconfigured so that they are initially disconnected and then physically(electrically) connected when they are connected to the DC inputterminals IN of the power module 500.

The junctions JN at which the electrodes ET1 and ET2 are connected withthe DC input terminals IN of the power module 500 are fixed to the DCinput terminals IN of the power module 500 by screws SC3 screwed intothe DC input terminals IN through the junctions JN, thus realizingreliable electrical connections.

The first capacitor module 302, the second capacitor module 304, thefirst power module 502, and the second power module 504 schematicallyshown in FIGS. 13A and 13B respectively correspond to the firstcapacitor module 302, the second capacitor module 304, the first powermodule 502, and the second power module 504 shown in FIG. 9. In thiscase, the first capacitor module 302 and the second capacitor module 304shown in FIG. 9 respectively include curved bending structures BD1 andBD2 in the halfway of the electrodes ET1 and ET2. The bending structuresBD1 and BD2 of the electrodes ET1 and ET2 can absorb and reduce stressin electrodes ET1 and ET2.

As shown in FIG. 12, the first capacitor module 302 includes a pair ofelectrodes TM1 connected to the battery 180 through the DC powerterminal blocks 810 mentioned later. Likewise, the second capacitormodule 304 includes a pair of electrodes TM2 connected to the battery180 through the DC power terminal blocks 810 mentioned later.

Each electrode TM1 of the first capacitor module 302 is connected to thefirst electric conductive board FC1 on one side and the second electricconductive board SC1 on the other side. Each electrode TM2 of the secondcapacitor module 304 is connected to the first electric conductive boardFC2 on one side and the second electric conductive board SC2 on theother side.

The electrodes TM1 and TM2 of the first capacitor module 302 and thesecond capacitor module 304 are respectively arranged on the side of thefront wall 232 of the housing 210. The electrodes TM1 and TM2 are thusarranged on the side of the front wall 232 of the housing 210 becausethe DC power terminal blocks 810 arranged in the terminal box 800 latermentioned in detail are positioned on the side of the front wall 232 ofthe housing 210.

Electrical connection between each electrode TM1 of the first capacitormodule 302 and the DC power terminal blocks 810 is established throughbusbars BB1. Electrical connection between each electrode TM2 of thecapacitor module CT2 and the DC power terminal blocks 810 is establishedthrough busbars BB2 (refer to FIG. 3).

As shown in FIG. 3, for example, the first capacitor module 302 and thesecond capacitor module 304 have a slight gap therebetween, and thefirst discharge resistor (not shown) and the second discharge resistor524 are arranged side by side in this gap along the axial direction. Asshown in FIG. 12, the gap between the first capacitor module 302 and thesecond capacitor module 304 is necessary to electrically connect thefirst capacitor module 302 and the second capacitor module 304 with thefirst power module 502 and the second power module 504, respectively,using the screws SC3 at the junctions JN of the electrodes ET1 and ET2of the first capacitor module 302 and the second capacitor module 304.Upon completion of these connections, the gap is effectively usedthrough arrangements of the above-mentioned first discharge resistor(not shown) and second discharge resistor 524.

Furthermore, the first capacitor module 302 of and second capacitormodule 304 are fixed to the base plate 320 mentioned later.Specifically, as shown in FIG. 12, the first capacitor module 302 andthe second capacitor module 304 have respective four fixing holes FH1and FH2 with embedded nuts at respective four corners. The firstcapacitor module 302 and the second capacitor module 304 are fixed tothe base plate 320 by screws SC4 (refer to FIG. 15) screwed into thefixing holes FH1 and FH2 through holes corresponding to the fixing holesFH1 and FH2 of the base plate 320. Specifically, the first capacitormodule 302 and the second capacitor module 304 are fixed to the baseplate 320 in a suspended condition.

(Terminal Box 800)

The terminal box 800 is fixed to the housing 210 of the power inverter200, and the DC power terminal blocks 810 and the AC terminal blocks 820are arranged therein.

The appearance of the power inverter 200, viewed from the side on whichthe terminal box 800 is attached is shown in FIG. 14. The terminal box800 is attached to the main sidewall 234 of the housing 210 using aplurality of screws SC5.

As shown in FIG. 2 to FIG. 4, a comparatively small opening 266 and acomparatively large opening 268 are formed on the terminal box 800respectively corresponding to the comparatively small opening 262 andthe comparatively large opening 264 formed on the main sidewall 234 ofthe housing 210. The terminal box 800 is provided with a partition 852which bisects the openings 266 and 268. The DC power terminal blocks 810are arranged at a space near the opening 266 and the AC terminal blocks820 are arranged at a space near the opening 268.

The DC power terminal blocks 810 include a noise filter which removesnoise from the DC power supplied from the battery 180 through the DCpower terminals 812. The noise filter prevents noise occurring inswitching operation of the power module 500 from leaking to outside.

From the DC power terminal blocks 810 extends a conductive materialhaving a rectangular cross section through the openings 266 and 262 toelectrically connect with a pair of terminals TT inside the housing 210arranged in the vicinity of the DC power terminal blocks 810. Theterminals TT are connected with the electrodes TM1 and TM2 of the firstcapacitor module 302 and the second capacitor module 304 through thebusbars BB1 and BB2, respectively, and then electrically connected withthe DC input terminals of the power module 500.

The AC terminal blocks 820 are connected with the lead terminals OL1 andOL2 inserted through the opening 264 of the housing 210 and the opening268 of the terminal box 800. The lead terminals OL1 are connected withthe AC output terminals OT1 of the first power module 502 throughbusbars BP1, and the lead terminals OL2 are connected with the AC outputterminals OT2 of the second power module 504 through busbars BP2.

The configuration of the terminal box 800 is such that the leadterminals OL1 include lead terminals OL1 w, OL1 v, and OL1 u which arerespectively connected to the W-phase connection terminal, V-phaseconnection terminal, and U-phase connection terminal of the firstrotating electric machine 130 through the AC power junction 822 preparedin the terminal box 800. Likewise, the configuration of the terminal box800 is such that the lead terminals OL2 include lead terminals OL2 w,OL2 v, and OL2 u which are respectively connected to the W-phaseconnection terminal, V-phase connection terminal, and U-phase connectionterminal of the second rotating electric machine 140 through the ACpower junction 822 prepared in the terminal box 800. The AC terminalblocks 820, including current sensors 536 and 538 for detectingalternating current, detect current flowing in each phase of the firstrotating electric machine 130 and the second rotating electric machine140.

The terminal box 800 is provided with the terminal box cover 846 on theupper face and the bottom 844 mounting the DC power terminal blocks 810on the bottom face. The present embodiment is provided with a terminalbox 800 through which the power inverter is connected with an externalDC power supply and each external rotating electric machine. Therefore,even if the position of each rotating electric machine or DC powersupply differs from model to model, this structure is effective forapplication without modifying the structure of the main unit or throughslight modifications. Base plate 320

FIG. 14 is a plan view showing a condition where the base plate 320 isarranged inside the housing 210. It also shows the rotating electricmachine control circuit board 700 mounted on the base plate 320.

The base plate 320 is configured as a control board bracket includingthe rotating electric machine control circuit board 700, and is fixed tothe housing 210 at a position above the capacitor module 300 inside thehousing 210.

Specifically, a plurality of convex parts PR are formed at almost equalintervals along the same direction on the inner surfaces of the housing210, allowing the base plate 320 to be supported on its fringes by theupper faces of the convex parts PR and arranged to a fixed position byscrews SC4 screwed into the upper faces of the convex parts PR throughthe holes formed on the fringes of the base plate 320.

Like the housing 210, the base plate 320 is made of a metal materialwith a favorable heat conductivity, for example, aluminum material inorder to improve the mechanical strength. Moreover, a concavo-convexpattern is formed on the surface on which the rotating electric machinecontrol circuit board 700 is mounted.

The above-mentioned concave of the base plate 320 is formed at a portionfacing to the distribution layer formation area on the base-plate sideof the rotating electric machine control circuit board 700, preventingthe distribution layer from coming into contact with the base plate 320made of metal material and thus preventing electrical short-circuit inthe distribution layer.

The convex of the base plate 320 is formed at a portion facing to thesecond block BST2 of the rotating electric machine control circuit board700, the comparatively large heat-generating semiconductors beingmounted on the opposite side thereof, making it easier to transfer heatfrom the semiconductors, etc. to the side of the second block. In thiscase, it would be also possible to insert a sheet made of an insulationmaterial with a favorable heat conductivity between the convex and therotating electric machine control circuit board 700 to preventelectrical short-circuit by the base plate 320 occurring in thedistribution layer formed on the opposite side of the semiconductormount area with respect to the rotating electric machine control circuitboard 700.

As shown in FIG. 3, a plurality of scattering bossed sections BS areformed on the surface of the base plate 320 facing to the rotatingelectric machine control circuit board 700, for example, in theabove-mentioned concave. The rotating electric machine control circuitboard 700 is fixed to the base plate 320 at these bossed sections byscrews SC6 (refer to FIG. 15) screwed through the screw holes formed onthe rotating electric machine control circuit board 700.

As mentioned above, the base plate 320 fixes the first capacitor module302 and second capacitor module 304 arranged below them by screws SC4screwed into the fixing holes FH1 and FH2 formed on four corners of thefirst capacitor module 302 and second capacitor module 304 through thescrew holes formed on the base plate 320.

Since the first capacitor module 302 and the second capacitor module 304are fixed to the base plate 320 arranged in contact with the housing210, the heat generated in the first capacitor module 302 and the secondcapacitor module 304 is easily transferred to the housing 210 throughthe base plate 320, offering excellent cooling effects.

(Rotating Electric Machinery Control Circuit Board 700)

FIG. 15 is a plan view showing the rotating electric machine controlcircuit board 700 mounted on the base plate 320 in the housing 210.

The rotating electric machine control circuit board 700 mountssmall-signal electronic components together with the connector CN. Theconnector CN is connected to a connector CN mounted on the gate drivecircuit board 6001 through the harness HN.

The rotating electric machine control circuit board 700 is fixed to thebase plate 320 by screws SC6 screwed into the base plate 320 throughscrews holes formed on, for example, four corners, fringes, and innerareas excluding the fringes, avoiding parts mount areas and distributionlayer formation area for connection of these parts.

With the above arrangement, the rotating electric machine controlcircuit board 700 makes it easier to prevent the central area frombending by vibration, etc., than a structure fixed to the frame only onfringes thereof, for example.

As mentioned above, since the rotating electric machine control circuitboard 700 is mounted on the base plate arranged in contact with thehousing 210, the heat generated from the rotating electric machinecontrol circuit board 700 is easily transferred to the housing 210through the base plate 320, offering excellent cooling effects.

Cover 290

The cover 290 is made of a lid material which closes the opening of thehousing 210 after storing the first power module 502 and second powermodule 504, gate drive circuit boards 6001 and 6002, first capacitormodule 302 and second capacitor module 304, base plate 320, and rotatingelectric machine control circuit board 700 in order in the housing 210.

The cover 290 is made of, for example, the same material as the housing210 and fixed to the housing 210 by screws SC7 screwed into the upperface of the housing 210 through screw holes formed side by side at equalintervals along the circumference on the fringes thereof (refer to FIG.5).

(Assembly Procedures of Power Inverter 200)

The following explains assembly procedures of the power inverter 200with reference to FIG. 2 to FIG. 4.

Step 1: A power module assembly unit comprising the first power module502, the second power module 504, the first drive circuit board 602, andthe second drive circuit board 604 is attached to the housing 210including the coolant inlet pipe 212 and the coolant outlet pipe 214. Atthis time, the cooling fins 506 and 507 of the power module assemblyunit are inserted into the openings 218 and 219 of the channel 216prepared at the bottom which is one side of the housing 210, and thenthe openings 218 and 219 of the channel 216 are sealed. Moreover, thebusbars for electrically connecting the first power module 502 and thesecond power module 504 with the rotating electric machines 130 and 140are fixed. When cooling fins 506 and 507 are inserted in the openings218 and 219, positioning can be performed around the openings, improvingthe workability of attachment work of the assembly unit.

Step 2: The signal connector 282, the noise reduction board 560, and thesecond discharge board 520 are attached to the power module assemblyunit. It would be also possible to attach the power module assembly unit580 to the housing 210 after attaching the signal connector 282, thenoise reduction board 560, and the second discharge board 520 to thepower module assembly unit.

Step 3: The capacitor module 300 including a plurality of capacitormodules 302 and 304 is inserted above the power module assembly unit 580and then wiring is performed.

Step 4: The base plate 320 is attached to a sidewall of the housing 210so that the base plate 320 be positioned above the capacitor module 300.The capacitor module 300 is fixed to the base plate 320 in this step.The workability of electrical connection between the capacitor module300 and the power module is improved by first making electricalconnection between the capacitor module 300 and the power moduleassembly unit and then attaching the base plate 320 to be located abovethem. However, it would be possible to first fix the capacitor module300 to the base plate 320 and then attach the base plate 320 with thecapacitor module 300 fixed thereto above the power module assembly unit580. In this case, since wiring work will be performed after attachmentof the base plate 320, the workability is improved by making work holeson some portions of the base plate 320 and the inner walls of thehousing 210.

Step 5: The rotating electric machine control circuit board 700 is fixedto the base plate 320 and then wiring connection is made. However, itwould be possible to first fix the rotating electric machine controlcircuit board 700 to the base plate 320 and then fix the base plate 320to a sidewall of the housing 210. The workability is improved and thereliability of wiring connection ensured by fixing the rotating electricmachine control circuit board 700 to the base plate 320 before fixingthe base plate 320 to the housing 210.

Step 6: The cover 290 is attached.

Step 7: The AC terminal blocks 820 is attached to the housing 210, andthe terminal box 800 including the DC power terminal blocks 810 isattached to the housing 210. The bottom plate 844 is attached to themain unit 840 of the terminal box 800 to make electrical connection, andthe cover 846 is attached to the main unit 840. It would be possible toattach the cover 290 after completion of attachment of the terminal box800 to the housing 210. Moreover, it would be possible to attach thecapacitor module 300 and the base plate 320 after completion ofattachment of the terminal box 800 to the housing 210.

(An Arrangement Aspect of Power Inverters 200 in Engine Room)

With the thus-configured power inverter 200, the front wall 232 of thehousing 210 is provided with the signal connector 282, and the coolantinlet pipe 212 and the coolant outlet pipe 214 for coolant circulation;the main sidewall 234 perpendicularly intersecting with front wall 232is provided with the terminal box 800 including the DC power terminalblocks 810 and the AC terminal blocks 820.

This allows other devices physically or electrically connected with thepower inverter 200 to be arranged collectively, for example, on thefront side or on the side of one of both side faces of the powerinverter 200. This allows other devices to be arranged also on the wallside of the space for arranging the power inverter 200, which iseffective for improving the flexibility of arrangement of the powerinverter 200.

FIG. 16 is a plan view showing an embodiment of arrangement aspect oftwo power inverters 200 in an engine room 102 in which an engine 120 isarranged at the center.

One power inverter 200 is placed on the left-hand side of the engine 120and on the back side of the engine room 102, and the other powerinverter 200 is placed on the right-hand side of this engine 120 and onthe back side of the engine room 102.

In this case, when the front wall 232 of the housing 210 of each powerinverter 200 is arranged in advance, the main sidewalls 234 of the powerinverters are respectively positioned in opposite directions.

With each power inverter 200, therefore, the signal connector 282, andthe coolant inlet pipe 212 and coolant outlet pipe 214CLO for coolantcirculation are oriented on the front side; and the terminal box 800 isoriented on the side of the engine 120.

As shown in FIG. 16, it is possible to arrange the two power inverters200 on the back side of the engine room, sandwiching the engine 120,allowing physical and electrical connections with other devices to beperformed easily.

The power inverter by the present invention is applied to, for example,a hybrid vehicle. The power inverter is not limited to this, but can beapplied to any kinds of power inverters that utilize at least a rotatingelectric machine and require an inverter to control it.

Each of the embodiments can be used either independently or incombination with other ones because effects in each embodiment can beobtained independently or in a synergetic manner.

What is claimed is:
 1. A power inverter comprising: a power module forinverting DC current to AC current; a current sensor for detecting theAC current; a control circuit board for providing a control circuit forcontrolling a drive of the power module based on the detected current bythe current sensor; a holding plate for holding the control circuitboard; an electric circuit; and a drive circuit board which drives thepower module, and is located adjacent the power module; wherein thepower module provides an AC bus bar for transmitting the AC current;wherein the AC bus bar extends in the direction of an opening portion ofa housing of said power inverter; and wherein the current sensor islocated at upper side of the drive circuit board and is connected to thecontrol circuit board by a signal wire.
 2. The power inverter accordingto claim 1, wherein the electric circuit is a capacitor module forsmoothing the DC current.
 3. The power inverter according to claim 2,wherein the holding plate holds the control circuit board at one faceand holds the capacitor module at the other face.
 4. The power inverteraccording to claim 1, wherein the opening portion of the housing is at aside wall of the housing which faces the electric circuit.
 5. The powerinverter according to claim 4, further comprising: a terminal box whichis fixed at the side wall of the housing so as to be close the openingportion; wherein the current sensor is installed in the terminal box.